Ware carrier for continuous kilns



F1 M. HARTFORD l ,@M

WARE CARRIER FOR CONTINUOUS KILNS F11ed Aprii 15, 1955 5 sheets-sheet 1 45 1451 "47 f4@ @1125 343 in kf l' 1 l/ j may W W36. F. M. HARTFORD I ZMLW WARE CARRIER FOR CONTINUOUS KILNS Filed April 13, 1955 3 Sheets-Sheet 2 dbtowwg mmm@ Mw W9 W36.. F, M. HARTFORD WARE CARRIER FOR CONTINUOUS KILNSl Filed April 15, 1955 5 Sheets-Sheet 6 Patented May 19, 1936 UNITED STATES FATENT OFFICE 12 Claims.

This invention relates to improvements in tunnel kilns of the continuously operating circular type and particularly concerns the movable ware supports by means of which ware is advanced through the preheating, firing zone and/or other zones of such a kiln by means of which the ware is subjected to desired conditions of heat treatment.

Considerable difficulty has been encountered in providing eiiicient wheeled carriers for advancing ware to be heat treated through a circular type of kiln and other equivalent heat treating chambers, such for instance as ovens or furnaces used in annealing, drying and other manufacturing operations. The usual kiln car comprises a hearth platform formed to include heat insulating or refractory materials, and upon which the ware to be heat treated is deposited for carriage through the heating zones of a heating kiln. These zones possess high operating temperatures, with the result that there is a considerable transmission of heat to the wheeled metallic carriage frames, operating on a trackway, and which are employed to effect the movable support of the hearth platforms. Even though precautionary measures are taken to prevent the transmission of heat from the firing chamber of a kiln below the hearth platforms and into the car pit, formed in the bottom of the kiln and in which the wheeled carriage frames operate, yet due to the very high temperatures which prevail in the kiln during operation, the metallic carriage frames or trucks become quite highly heated, with the result that the metal of which they are formed expands or distorts, so that there is not a true alignment or registration .of the carriage or truck wheels with the circularly disposed stationary tracks on which the carriage frames operate. This distortion of the carriage frames results in a very considerable amount of friction and msalignment of flanged wheels with associated tracks, so that when a train of such carriers is being advanced through an operating kiln, a considerable expenditure of power is necessitated to effect the advancement, due to friction between relatively movable parts which is a direct result of distortion of metallic members when highly heated. Also there is a tendency for the wheeled trucks or carriage frames to jump the tracks, which necessitates shutting down the operation of the kiln until the jambing condition is removed.

It is therefore one of the primary objects of the present invention to provide improved ware supporting means for circular kilns wherein use is made .of a plurality of separable segmental hearth sections or platforms placed end to end in circular order for the support of the Ware to Vbe treated, carriage frames being disposed beneath these hearth sections in such manner that 5 each carrier frame will serve to support the adjoining ends of a pair of hearth sections, and wherein improved means are provided for uniting the carriage frames and confining their travel to a predetermined circular course which does not vary under expansion and contraction of the metal running gear disposed in the car pit of a kiln.

It is another object of the invention to construct the carriage frames so that they will be freely separable from the segmental hearth sections and will have minimum surface contact with the hearth sections, whereby to minimize the transmission of heat from the hearth sections to the carriage frames by conductance, and it is a further object of the invention to construct the carriage frames to provide for the free circulation of air around the same in order to quickly carry away the heat of the car pit and the metal members disposed therein.

For a further understanding of the invention, reference is to be had to the following description and to the accompanying drawings, in which:

Fig. 1 is a horizontal sectional view taken through a continuously operating circular kiln suitable for use in connection with the present invention;

Fig. 2 is a vertical transverse sectional View taken through the kiln on the plane indicated by the line II-II of Fig. l;

Fig. 3 is a vertical sectional View taken through the kiln on the line III-III of Fig. 2;

Fig. 4 is a similar View of a modied form of running gear; 40

Fig. 5 is a vertical transverse sectional view on the line V-V of Fig. 4;

Fig. 6 is a horizontal sectional view on the plane disclosed by the line VI-VI of Fig. 4;

Fig. '7 is a detail View;

Fig. 8 is a detail perspective View of one of the roller supports disclosed in Fig. 2.

Referring more particularly to the drawings, and especially to the form of the invention illustrated in Figs. 1 to 3, I have disclosed a continu- 50 ously operating circular type of kiln adapted for the heat treatment of molded ceramic articles, although of course the kiln may be employed in many other capacities. The kiln comprises a heat-confining Wall structure of circular or segmental formation. In this instance, the wall structure has been shown as comprising a segment of approximately 270 of a complete circle, thereby providing spaced ware receiving and discharging ends 2 and 3 respectively. The specific formation of the Wall structure I is, of course, subject to considerable variation and I particularly do not desire to limit myself to the formation thereof as depicted in Figs. l to 3 since the running gear, comprising the subject of the present invention, may be employed in connection with other substantially circular types of kilns differing greatly from the form herein illustrated.

Generally, however, the wall structure I, as shown, provides a suitable foundation 4, preferably of concrete, which is employed to support a frame Work 5 of structural steel members, which frame work also includes vertically upstanding buckstays 6 united at their upper ends by tie rods 1. Supported by the frame work 5 and its associated buckstays are the bottom, side and roof walls 8, 9 and I0 respectively of the kiln. These walls, as usual, are formed from heat insulating and/or refractory materials and are assmbled to produce within the wall structure a substantially circular tunnel II through which the ware to be heat treated is supported and passed on movable platforms in a circular path. The pre-heating section of the tunnel is indicated by the letter A, the high temperature or ring section by the letter B, and C indicates the rear discharge section. The sections A and B are of greater transverse width than the discharge section C in order to provide arcuate passageways D for the passage of high temperature combustion gases, introduced into the firing section B by means of the hydrocarbon fuel burners or other equivalent heating means I2. The passages D may gradually diminish in cross sectional area from thesection B to the end of the section A in order to compensate somewhat for the shrinkage in volume of the combustion gases due to their cooling and thereby maintain the thermal efiiciency of the kiln. The stack outlets I3 connect with the ends of the passages D in the zone A for withdrawing the cooled gases.

The passages D are formed between'the side walls 8 ofthe kiln and the tunnel panels I4. These panels are composed of arcuate sections suitably joined at their ends and are preferably supported by means of blocks I5 which rest upon the upper surface of the bottom wall 8 on opposite sidesv of the car pit I6. The blocks I5 also support inclined panels I'I. Preferably, the panels I4 and I1 are formed from a suitable material having a high rate of thermal conductivity. In practice, these panels become highly heated and the heat radiated from the inner surfaces thereof is directed upon the Ware to be heat treated during the passage of the latter through the arcuate tunnel I I. YThe panels serve to prevent the gases of combustion, which travel through the passageways D, from coming into direct contact with the ware undergoing heat treatment. It is of course within the range of the invention to use what may be termed a direct fired kiln, wherein the combustion gases directly contact with the ware during heat treatment, rather than'the indirect type of heating here specifically disclosed wherein the combustion gases are substantially removed from direct contact with the ware passing through the tunnel. Y

In lieu of employing conventional kiln cars for supporting the ware during passage thereof through the kiln, and which conventional cars are objectionable in many particulars in a circular type of kiln, I have provided an improved running gear which, in the form of the invention disclosed in Figs. 1 to 3, embodies a plurality of stationarily supported flanged or grooved rollers I8. These rollers are carried by axles I9 which are received within bearing brackets 20', mounted transversely of the pit I6. The brackets 20 rest upon stationarily mounted base plates 2I, and the ends of the latter are provided with set screws 22, which engage with the ends of the brackets 20 so that the latter may be adjusted to control and maintain the rollers I8 in proper operating positions within the bottom of the pit.

Arranged to engage with the upper surfaces of the rollers I8 and suitably supported thereby are transversely spaced concentric rings 23 which effect the support of transversely extending carriage or sub-frames 24 which are provided at their ends with vertical cross webs 25. Seated on the upper surfaces of the cross webs 25 are. the spaced vertically depending flanges 26 of the metallic platform frames 2'I which support platforms or hearth sections 28 of a refractory material. dered as at 29 along their upper longitudinal edges for cooperation with overhanging ledges 30 formed in connection with the bottom wall 8 of the kiln adjacent to the upper edges of the car pit I6. The sections 28 are adapted to receive pier frames 3I which, in turn, receive the shelves 32 upon which the ware to be heat treated is directly supported for passage through the tunnel II. The frames 21 also include depending vertically disposed ns 33 which cooperate with troughs 34 stationarily supported in connection with the side walls of the pit I6, and which troughs are adapted to contain sand, or other similar material, to prevent or minimize as far as possible the escape of heat from the tunnel region into the car pit.

By virtue of this construction of the running gear, free and adequate circulation of air around the metallic portions thereof is permitted so that overheating of these portions will be prevented and long wear and use obtained. The transmission of heat to the rollers I8 and the rings 23 is further prevented by the construction of the transversely disposed sub-frames 24 and the substantially rectangular intersections of the cross webs 25 and the flanges 26 of the platform frames. This construction provides an extremely open one for the circulation of air and removal of heat and also reduces to a minimum the area of contact between the platform frames 21 and the sub-frames 24. The construction additionally serves to provide an improved circular running gear, characterized by freedom from distortion under operating temperatures and wherein there are no through members extending from the platform bodies to the supporting wheels or axles. The cross webs 25 are preferably shouldered as at 35 to assist in the positioning of the depending fianges 26 of the platform frames 21, restraining the latter against undesired transverse movement. Similarly, the sub-frames 24 may be provided with depending lugs 3S, which engage with the sides of the rings 23 to avoid undesired transverse movement of the sub-frames relative to saidrings. It will be understood that any suitable vmechanism may be employed for imparting motion at a controlled rate of travel to the platform The hearth sections are shoul-` assembly supported for movement on the rollers I 8.

In general, therefore, this construction provides a free, readily turnable ware supporting means for a circular kiln which may be operated when normally loaded with but a fraction of the power heretofore required in moving standard kiln cars around a circular trackway. There is no tendency on the part of the ware supporting mechanism to bind or jamb Within the tunnel and its free turning status is maintained under all temperature ranges found in the operationof a kiln of this character.

In the form of the invention disclosed in Figs. 4.- to 7, arcuate platform frames 21a are disclosed which support refractory platform or hearth bodies 28a, also of arcuate formation, upon which the ware to be heat treated is supported in substantially the manner disclosed in Fig. 2. The spaces formed between the adjoining ends of the platforms 28 and 28a are sealed by means of gaskets shown at 38. In effecting the support of the platforms 21a and 28a, I have provided a plurality of carriage frames or trucks 39 which are provided at their lower ends with journals for the reception of axles 40, the latter carrying at their ends flanged wheels 4| arranged for engagement with stationary concentric track rails 42, suitably supported in connection with the bottom of the pit I6. The frames 39 are arranged in vertical alignment with the ends of the bodies 21a and 28a. and include widened beds 43 provided with upstanding integral pads 44 which receive the frames 21a, the pads 44 serving to space the beds 43 from extended thermal contact with the frames 21a. Depending from; the under side of the beds 43 are ears 45 adapted for the reception of cross pins 46 which unite said ears with the upstanding flanges of a substantially H-shaped structural steel ring 41. Preferably, the cross pins 4B are somewhat loosely mounted in the apertures formed in the lower portions of the ears 45. By this construction, the ring 41 is supported from the wheeled trucks 39 so that power may be imparted to said ring, by the use of any suitable mechanism, to move the entire ware supporting train.

The forward ends of the beds 43 include forwardly projecting integral tongues 48 which, as shown in Fig. 7, have their outer ends apertured for the reception of cross bolts 49 carried by the vertical flanges of the ring 41. In order to adjust the relationship of the Wheel axes with respect to the true center of the kiln, the ring 41 is provided, in registration with each tongue 48, with set screws 5i). By the adjustment of the set screws 59, the axles 4t of the wheels 4| may be so regulated with respect to the true center of the kiln as to enable the wheels 4I to rotate over the circular tracks 42 with but a minimum of flange friction, thus providing a smooth and freely operating running gear.

In both forms of my invention here disclosed, a true circular running gear is afforded for the efficient rotation and ventilation of the platform sections and carriage frames and since the latter are composed of transversely disposed sections with but a minimum of surface contact, heat transmission through said members is retarded to such a degree that distortion is eliminated together with other attendant evils due to the overheating of metallic running gear parts.

What is claimed is:

1. Carrier mechanism for transporting Ware through continuous circular kilns comprising segmental hearth sections placed end to end in circular order, carriage frames freely separable from and supporting said hearth sections below the adjoining portions thereof, and wheels cooperative with the carriage frames for the anti-friction support of the hearth sections to facilitate turning movement thereof.

2. Carrier mechanism for continuous kilns comprising a plurality of segmental hearth sections arranged end to end in circular order, continuously united supporting members upon which said hearth sections are loosely positioned, and antifriction members for said supporting members.

3. Carrier mechanism for continuous kilns,

comprising a plurality of horizontally disposed segmental hearth sections adapted to be placed end to end in circular order, transversely disposed carrier frames upon which the ends of said hearth sections are loosely positioned, anti-friction supporting members for said carrier frames, and means conningsaid carrier frames for movement ina fixed circular course. 4. Carrier mechanism for continuous circular kilns, comprising a plurality of separable segmental hearth sections placed end to end in circular order, carrier frames disposed beneath said hearth sections, each carrier frame serving to supportthe adjoining ends of a pair of hearth sections, and means uniting said carrier frames and for confining their travel to a predetermined circular course.

5. Carrier mechanism for continuous kilns, comprising a plurality of segmental car bodies adapted to be arranged end to end in circle-forming relationship, sub-frames provided with track engaging wheels and arranged beneath said bodies for effecting their movable support, and a single rigid ring member uniting said sub-frames for uniform and simultaneous movement.

6. Carrier mechanism for transporting ware through continuous kilns, comprising a plurality of arcuate horizontally disposed car bodies adapted to be arranged end to end in circle-forming relationship, transversely extending sub-frames arranged beneath the adjoining ends of said bodies, a circular trackway, wheels carried by said sub-frarnes and engaging with said trackway, and a single rigid ring member uniting said subframes in spaced order and for unitary movement, said car bodies being freely separable from the sub-frames.

'7. Carrier mechanism for transporting ware through continuous kilns, comprising a plurality of horizontally disposed segmental ware-supporting platforms, said platforms being arranged end to end in circle-forming relationship, trucks freely separable from said platforms and supporting the latter beneath the adjoining ends thereof, each of said trucks being provided with wheels arranged for engagement with a substantially circular trackway, a ring member arranged beneath said platforms, and a tongue formed with each of said trucks and connected with said ring member.

8. Carrier mechanism for transporting ware through continuous kilns, comprising a plurality of horizontally disposed segmental ware-supporting platforms, said platforms being arranged end to end in circle-forming relationship, trucks freely separable from said platforms and supporting the latter beneath the adjoining ends thereof, each of said trucks being provided with wheels arranged for engagement with a substantially circular trackway, a ring member arranged beneath said platforms, and a tongue formed with each of said trucks and adjustably connected with said ring member for regulating the radial relationship between said trucks and the center of said trackway.

9. Carrier mechanism for transporting ware through continuous kilns, comprising a plurality of horizontally disposed car bodies, transversely spaced vertical ilanges depending from said bodies, transversely extending sub-frames having upright cross Webs arranged to engage with the flanges of said car bodies, a plurality of spaced stationary brackets, anged rollers carried by said brackets, and rigid members engaging with said rollers and With the under surfaces of said sub-frames.

10. In a continuous kiln, a carrier mechanism comprising a plurality of spaced stationary brackets mounted in the bottom of a circular car pit, iianged rollers carried by said brackets, concentric ring members engaging With said rollers, a plurality of cross members arranged at intervals on said rings, said cross members being provided with upstanding Webs, a plurality of arcuate car frames arranged end to end in circle-forming relationship, said car frames being provided with spaced depending circular flanges arranged to rest upon the upper edges of said webs, and a refractory body mounted on each of said car frames.

l1. In a continuous kiln having a circular car pit, a plurality of car brackets stationarily mounted in the bottom of said car pit, ilanged rollers carried by said brackets, means for adjusting the operative positions of said rollers transversely of the car pit, spaced concentric rings mounted on said rollers, cross members supported by said rings at predetermined intervals, said cross members being provided With upstanding Webs, a metallic car frame provided with depending arcuate flanges arranged to rest upon the upper edges of said Webs, shouldered means for maintaining the vertically aligned relationship of said rings, cross members and car frames, and a body of refractory material carried by each of said car frames.

12. Carrier mechanism for continuous annular kilns comprising a plurality of segmental waresupporting platforms placed end to end in circular order, transversely extending sub-frames positioned beneath the adjoining ends of said platforms, a circular trackway, Wheels carried by said sub-frames and engaging with said track- Way, downwardly projecting lugs provided on said sub-frames, and a ring member supported by said lugs, said ring member serving to unite 25 said sub-frames in spaced order and for unitary movement.

FRANK M. HARTFORD. 

